This article traces the history and development of the —0.850 V E (copper sulfate electrode) potential criterion over the last 60 years with respect to thermodynamic considerations and empirical testing in both the laboratory and field. The significance of reference electrode position and IR-drop voltages […]
External corrosion of iron watermains has been a problem for municipalities for over 100 years. The three main causes of corrosion, in a historical context are: stray currents from electrified transit systems dissimilar soils galvanic corrosion All of these causes remain with us today, although […]
Interference can be defined as any electrical disturbance on a structure caused by a stray current. In this context, ‘stray’ refers to a current in an unintended path, although it is recognized that current will take all available paths in inverse proportion to the relative […]
Prestressed concrete cylinder pipe (PCCP) used for water and sewer transmission service is composed of a thin wall steel cylinder, lined on the interior and exterior with cement mortar, and reinforced by prestressing wire either wrapped around the steel cylinder or embedded in the exterior […]
A 1985 study conducted by the Canada Mortgage and Housing Corporation stated that the overall cost of repairs to damaged parking structures in Canada was estimated at 1.5 to 3.0 billion dollars. Little has done in the intervening years to reduce these costs on existing […]
Potential and current fluctuations on oil and gas pipelines attributed to telluric currents have been observed for many years by corrosion control personnel when conducting routine cathodic protection performance surveys. The impact of these geomagnetically induced currents has generally been considered more of a nuisance […]
The service life of Mg anode cathodic protection systems installed on iron water mains has, in some instances, been significantly less than design calculations would predict. Testing of high-potential Mg alloys from various suppliers using the ASTM G97-89 test method indicates that efficiencies are widely […]
The impact of telluric current activity on the corrosion control systems on pipelines in northern regions and cold climates is examined. Three specific areas of concern are identified These factors are corrosion of the pipe during positive cycles of the telluric disturbances, accurate measurement of […]
The conventional understanding of the cathodic protection mechanism is illustrated in the definition of cathodic protection arising from the research of Mears and Brown in 1938. That is, cathodic protection is complete when the corrosion cell cathodes are polarized electronegatively to the open circuit potential […]
The analysis of indirect inspection data is a critical factor in conducting a successful ECDA process. This paper covers two lessons learned recently when dealing with bonded pipelines along common rights-of-way and also with equalization currents. The “old” challenge of differentiating between “threat” related versus […]
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